I agree, this article is a mis-characterization of what 'off-grid' should mean: not only do these sorts of cabins have all modern utilities, they're also constantly serviced by the owners, who themselves need to drive around to each of them, probably destroying any 'ecological' benefit they might otherwise have.
In nordic countries cabins similar to this have existed for centuries - the only change here is that they've become a commodity for middle-class city-dwellers.
Also by placing them in the middle of forests instead of (mostly) near the edges or alongside some water, these cabins simply give affluent vacationers the chance to experience the illusion of 'returning to nature' or living in some idealized 'primitive' state, at the cost of someone else needing to (literally) clear up their shit afterwards, and also transport water and other essentials deep into the woods, which would otherwise be free of traffic and disturbance to the animals and flora that have been there for millennia.
As for the suggestion in the article that they could extend the season through the winter with some sort of battery top-up (because of the lack of natural light), anyone who has experienced trying to get to a place out in the countryside (and even near to a road, let alone in the middle of a forest), after a meter of wet snow has fallen would never even dream of suggesting this as a vacation option.
Not only would the experience turn into one of raw survival (which might even be doubtful if the heating failed), but living in an isolated spot with barely 3 or 4 hours daylight each day would be stretching most people's endurance.